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Single‐plant chambers to control humidity for pathological studies
Author(s) -
BUTLER D. R.,
REDDY R. K.,
WADIA K. D. R.
Publication year - 1995
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/j.1365-3059.1995.tb02710.x
Subject(s) - humidity , relative humidity , biology , horticulture , germination , dew point , dew , botany , meteorology , physics , condensation
The construction of a set of controlled‐humidity chambers for single plants is described. Accurate control of relative humidity (r.h.) between 40% and 99% was achieved by mixing dry air with a saturated air stream using solenoid valves controlled by a programmable data logger. At values of r.h. >90%, mean values over periods greater than 1 min were constant to within ±0·1% and spot measurements at 3 s intervals were within 0‐3% of the mean value. The system responded to a step change of r.h. in about 6‐10 min and diurnal changes of r.h. were reproduced, similar to those observed in nature. The stability of control made it possible to differentiate between the requirement of liquid water and very high humidity (98% r.h.) for conidial germination and subsequent infection of groundnut by Phaeoisariopsis personata , the cause of late leaf spot disease.